Process and device for temporarily holding and releasing objects

ABSTRACT

A process and device utilizing the memory characteristics of cross-linked polymers for temporarily holding and releasing parts or components is presented. In a first step, a polymeric material or part capable of being cross-linked is formed into a first &#34;memory&#34; shape. Thereafter, in a next step, the polymer is cross-linked via irradiation or any other suitable technique to fix or lock the polymer into the first memory shape. Next, the polymer is heated and deformed to a second shape and thereafter cooled to lock in that second shape. During the deformation process, the cross-linked polymer will preferably be deformed about a second component or part so that upon cooling, the second part will be tightly held by the deformed polymer. Thus, the second part or component will be temporarily held for any desired length of time. When it is desired to release the second part, the deformed cross-linked polymer part is subjected to a second heating (above its transition temperature) whereupon the polymer will revert back to its first memory shape and thereby release the second part or component held therein. In an alternative embodiment of the present invention, the cross-linked deformed polymeric material may be itself held; the deformed cross-linked material releasing itself from the holder upon reheating (above its transition temperature).

BACKGROUND OF THE INVENTION

This invention relates to several useful applications of cross-linkedpolymers utilizing the inherent memory phenomenon associated with suchcross-linked polymeric materials to effect a temporary attachment of afirst part to a second part. More particularly, this invention relatesto a device and method of using cross-linked polymeric materials whereina polymer is formed to a first "memory" shape; thereafter the shapedpolymer being cross-linked to lock in that first "memory" shape. Next,the shaped polymer is heated and deformed to a second shape; and thencooled to lock in that second shape, the deformed shape effectingattachment or holding to another part. This is followed by a secondheating above the polymeric transition temperature which will act torelease the held part as the deformed cross-linked polymer reverts backto its first "memory" shape.

The memory characteristics of cross-linked polymeric materials is wellknown to those skilled in the art. This novel property of cross-linkedpolymers has been practically utilized in several prior artapplications. For example, shrink tubing and the like is one such wellknown application. In shrink tubing, the cross-linked polymer isexpanded and upon heating, reverts back to its original smaller shape.Other examples include U.S. Pat. No. 3,382,121 to Sherlock whichdiscloses a process for preparing a heat recoverable sleeve with afusible insert held in contact therewith. An extruded or formedlongitudinally oriented plastic insert is placed adjacent to arecoverable plastic member and the assembly is thereafter heated to atemperature sufficient to release the stresses in the insert induced byorientation; and to cause the insert to retract in length, and tightlycling to, the recoverable member. In the assembly thus produced, theinsert is brought into abutting relationship to the recoverable member.

U.S. Pat. No. 4,343,844 to Thayer et al discloses a shrinkable sleeve ofminimal outside diameter made from heat shrinkable material having anelastic memory and adapted to be secured to the end of an electricalcable having one or more electrical conductors and/or tubes extendingtherefrom to provide a barrier to the flow of gas or vaporstherethrough. When the sleeve is in an expanded state, a cavity at oneend receives the conductor bundle. The sleeve contains one or moreinternal channels at the opposite end thereof that are separated fromeach other by walls that are related to the wall of the remainder of thesleeve.

In U.S. Pat. No. 3,597,372 to Cook, a method is disclosed for makingelastomeric products which have the properties of elastic deformationsubstantially equal to that of true elastomers, and, upon theapplication of heat, recover to the original cross-linked size. Acomposition is formed which is then cross-linked by ionizing radiation.The cross-linked article is then heated to a temperature sufficientlyhigh to soften the thermoplastic component. The deformed article iscooled or quenched while still under the external deforming stress. Thearticle is now in the heat-recoverable state, but may be left for anindefinite period of time at room temperature without danger of itsrecovering back to its original size and shape.

Evans U.S. Pat. No. 3,847,721 discloses an article processed to be heatrecoverable in involute fashion to an overlapping, generally cylindricalconfiguration. The articles are initially heat recoverable to across-section "S". The article can be deployed around a substrate to beprotected, the arcuate edge portions thereof positioned in interlockingrelation, and heat applied to the interlocked edge portion to form abonded seam.

Finally, U.S. Pat. No. 4,440,712 to Imgram discloses a process for thepreparation of shaped articles, particularly tubular shaped polymericarticles, comprising moldable and cross-linkable synthetic plasticmaterial, into a first molded shape, cross-linking the plastic materialat a temperature in excess of the crystalline melting point of material,subjecting the cross-linked first shape to a working operation to form asecond configuration shape; and subjecting specific areas of the secondshape to a heat treatment thereby forming a deformation in the specificarea. Other prior art patents of general interest which utilize thememory characteristics of cross-linkable polymeric materials includeU.S. Pat. Nos. 2,981,668, 2,086,242, 3,110,553, 3,318,994, 3,370,112,3,387,065, 3,396,460, 3,420,363, 3,526,863, 3,959,052, and 4,033,534.

It will be appreciated that none of the above described and discussedprior art patents disclose a method of utilizing the inherent "memory"characteristic of cross-linkable polymers for those applications whereina temporary attachment of a first part to a second part is effected.Such temporary holding of cooperating parts is necessitated in a myriadof industrial, agricultural, construction and safety applications toname but a few. For example, in automatic assembly operations, componentparts must be temporarily held and oriented so as to be provided to anassembly at a specific time and place. Similarly, in the constructionfield, fasteners, terminals, rivets and other items must be temporarilyheld in a substrate or bin when being used in automatic insertiondevices. Fire safety and similar safety applications require parts andassemblies which will be automatically removed to expose sprinklersystems or other devices during fires.

Accordingly, it is an object of the present invention to provide adevice and method of using a cross-linkable polymeric material whichutilizes the inherent "memory" characteristic thereof to effecttemporary holding or attachment between several parts or components in avariety of industrial, agricultural, construction, safety and otherapplications.

It is still another object of the present invention to provide a processand device for utilizing the "memory" characteristic of cross-linkedpolymers wherein a polymer "part" is formed to a first shape andcross-linked to hold that first "memory shape"; the cross-linked polymerpart being thereafter heated and deformed to temporarily lock on to andhold a second "part", and the polymer part being cooled to lock thesecond shape therein. Thereafter, when desired, the deformed polymerpart is heated above its transition temperature wherein it will revertback to its first memory shape and the held or secured second part willbe released. The process of the present invention will thus takeadvantage of the memory characteristic of cross-linked polymers byholding and thereafter releasing components at specified times andplaces.

Other objects and advantages of the present invention will be apparentto and understood by those skilled in the art from the followingdetailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, wherein like elements are numbered alikein the several figures;

FIGS. 1A-1D are cross-sectional elevation views disclosing the memoryeffect of cross-linked polymers in existing shrink tubing in accordancewith the prior art;

FIGS. 2A-2D are cross-sectional elevation views of a process utilizingcross-linked polymeric materials wherein a component or part istemporarily held and thereafter released in accordance with the presentinvention;

FIGS. 2AA-2DD are elevation views along the lines AA--AA, BB--BB,CC--CC, and DD--DD of FIGS. 2A-2D, respectively.

FIG. 3A-3D are cross-sectional elevation views, similar to FIGS. 2A-2D,and showing the holding and releasing process for round objects inaccordance with the present invention;

FIGS. 3AA-3DD are elevation views along the lines AA--AA, BB--BB, CC--CCand DD--DD of FIGS. 3A-3D, respectively.

FIGS. 4A-4C are perspective views, partly in cross-section, showing theholding and releasing process for a plurality of round objects inaccordance with the present invention;

FIGS. 4AA-4CC are cross-sectional elevation views showing the holdingand releasing process of FIGS. 4A-4C, respectively.

FIGS. 5A-5D are perspective views showing the holding and releasingprocess for a plurality of cylindrical objects in accordance with thepresent invention;

FIGS. 5AA-5DD are enlarged perspective views of a portion of the holdingand releasing process shown in FIGS. 5A-5D, respectively.

FIGS. 6A-6D are cross-sectional elevation views showing the holding andreleasing of a panel in accordance with the present invention;

FIGS. 7A-7D are cross-sectional elevation views of another alternativemethod of holding and releasing a panel in accordance with the presentinvention;

FIGS. 8A-8D are perspective views showing a universal process forholding and releasing objects of complex shape in accordance with thepresent invention;

FIGS. 9A-9D are cross-sectional elevation views showing still anotherembodiment of the holding and releasing of a panel in accordance withthe present invention;

FIGS. 10A-10D are cross-sectional elevation views showing yet anotherembodiment for holding and releasing panels in accordance with thepresent invention;

FIGS. 11A-11D are cross-sectional elevation views showing the holdingand releasing of a container cap in accordance with the method of thepresent invention;

FIGS. 12A-12D are elevation views of a container for fluid in accordancewith the present invention; and

FIG. 13 is a flow diagram of the process in accordance with the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to a novel method of, and device for,temporarily holding or engaging and thereafter releasing a plurality ofparts or components. This process and device may be utilized in a verylarge number of applications including, but not limited to the fields ofindustry, agriculture, consumer goods, safety equipment andconstruction. The method of holding and releasing in accordance with theprocess of the present invention is characterized by a novel use of thewell known memory properties of cross-linkable polymeric materials. Asdiscussed hereinabove, the memory characteristic of cross-linkedpolymers is well known and has been adapted in several knownapplications; most noticeably in the heat shrink field. An example ofthe prior art application of the memory effect of cross-linked polymersis described in FIGS. 1A-1D. Thus, in FIG. 1A, a cross-linked polymerictubing is shown generally at 10 having a diameter of D1. The D1 diameterof tubing 10 may be defined as its memory shape. In FIG. 1B,cross-linked polymeric tubing 10 has been heated and deformed to asecond shape and a second diameter D2; and thereafter cooled to lockthat second shape. Next, a second part, such as a wire conductor 12,having a diameter equal to or greater than D1 is inserted into tubing 10as shown in FIG. 1C. Finally, upon a second heating, polymeric tube 10will shrink and recover back to its original diameter D1 thus forming asnug fit about the inserted wire conductor 12 as shown in FIG. 1D.

While the heat shrink tubing of FIG. 1 and similar applications of theprior art have found great utility in many practical applications, othermethods of practically and efficiently utilizing the memorycharacteristics of cross-linked polymers are needed. The presentinvention overcomes this deficiency by the method and device disclosedherein wherein the memory characteristics of cross-linked polymers isused to temporarily hold or engage and then release parts or components.Turning now to FIG. 13, a flow diagram in accordance with severalpreferred embodiments of the present invention is shown. In a first stepA, a polymeric material or part capable of being cross-linked is formedinto a first "memory" shape. Thereafter, in step B, the polymer iscross-linked via irradiation or any other suitable technique (i.e.,chemical additives) to fix or lock the polymer into the first memoryshape. Next, the polymer is heated and deformed to a second shape (stepC) and thereafter cooled to lock in that second shape (step D). Duringthe deformation process, the cross-linked polymer will preferably bedeformed about a second component or part so that upon cooling (step D),the second part will be tightly held or engaged by the deformed polymer(step F). Thus, the second part or component will be temporarily heldfor any desired length of time. When it is desired to release the secondpart, the deformed cross-linked polymer part is subjected to a secondheating (above its transition temperature) whereupon the polymer willrevert back to its first memory shape (step B) and thereby release thesecond part or component held therein (step G). Accordingly, heating thedeformed polymeric material above its transition temperature will returnit to its original memorized shape. This process of temporarily holdingand then releasing parts and the device to practice the process is wellsuited for many practical applications as will be discussed in greaterdetail below.

It will be appreciated that any polymer which can be cross-linked byhigh intensity ionizing radiation (electron beam, cobalt 60, etc.) maybe used in accordance with the process of the present invention.Suitable cross-linkable polymers include, but are not limited topolyethylene, polyethylene co-polymers such as ethylenevinylacetate(EVA), polyvinylchloride (PVC), cross-linkable elastomers, blends of PVCand elastomeric materials and cross-linked EVA/wax blends.

The novel process as described above in connection with the flow diagramin FIG. 13 is further exemplified by the numerous examples disclosed inFIGS. 1-12. Turning now to a discussion of the several examples, inFIGS. 2A and 2AA, a cross-linked polymeric strip or base 14 having aplurality of cylinders 16 extending outwardly therefrom, each cylinderhaving an opening 18 therethrough, is shown. Strip 14 and cylinders 18have been formed from a cross-linkable polymer and have been subjectedto radiation to effect cross-linking; and to lock in the memory shape asis shown in the Figures. Thereafter, metal cylindrical rods 20 areplaced into openings 18 (FIGS. 2B and 2BB) and the cylinders 16 are thenheated and deformed at a first end 22 thereof to effect a snug hold onthe rods 18 as shown in FIGS. 2C and 2CC. Cylinders 16 are then cooledto lock in the deformed shape and thereby temporarily hold the rods instrip 14 for any desired length of time. When desired, cylinders 16 arethen heated a second time above the transition temperature of thecross-linked polymer whereupon the deformed ends 22 of cylinders 16 willrevert back to the first memory shape shown in FIG. 2A and therebyrelease the rods 18 as is clearly shown in FIGS. 2D and 2DD.

It will be appreciated that while cylindrical rods 18 have been shown inFIG. 2, any part or component used in a given assembly operation may beused in conjunction with the particular embodiment of the presentinvention shown herein. For example, in FIGS. 3A-3D and 3AA-3DD, a roundobject 20 is used in a strip 14' in a process similar to that shown inFIG. 2. Thus, in FIGS. 3A-3C, cylinders 16' are formed and cross-linkedto a first memory shape and thereafter are heated, deformed and cooledto a second shape (FIGS. 3B and 3BB); this second shape acting to closeoff or seal the first end 22' of cylinders 16'. Next, a round object 20is inserted from the end 24 opposite the sealed end 22' whereupon thedeformed sealed end 22' will hold round object 20 for any desired lengthof time. Finally, deformed and sealed end 22' is subjected to a secondheating whereupon the deformed polymer will revert back to its originalfirst memory shape and the round objects 20 will be released (FIG. 3D).

A cross-linked strip having a plurality of holding members extendingtherefrom such as strip 14 in FIGS. 2 and 3 offers a favorablealternative to many industrial and other applications which necessitatethe automatic feeding or assembly of components or parts at selectedtimes and places. For example, presently, many assembly operations ofsmall parts utilize large bin feeders for feeding the parts such asthose shown in FIGS. 2 and 3. However, such bin feeders do not functionadequately for complex shapes and deformable parts i.e., springs. Themethod of the present invention for temporarily holding and releasingobjects (upon heating) utilizing a cross-linked polymer structure suchas shown in FIGS. 2 and 3 would alleviate such problems.

Turning now to FIGS. 4A-4C and 4AA-4CC, another method of practicing theprocess of the present invention is shown. In FIGS. 4A and 4AA, asection of a cross-linkable polymeric cylindrical tube 26 is shown. Tube26 has an opening 28 therethrough and a longitudinal slot 30 whichprovides access from the inner opening 28 to the outside. The tubularconfiguration as shown in FIG. 4A is then subjected to irradiationwhereupon the polymer will lock into a first memory shape. Next, objectsor parts such as round items 32 are provided within the interior 28 oftube 26 via slot 30. Thereafter, tube 26 is subjected to heating,deformation and cooling to effect closure of slot 30 so that the rounditems 32 may not escape (FIGS. 4B and 4BB). The tube is then rotated180° as indicated by the arrow in FIG. 4BB so that slot 30 is nowaligned with round object 32. At a desired time, tube 26 is subjected toa second heating (above the transition temperature of the polymer) sothat tube 26 will revert back to its original memory shape whereuponslot 30 will once again open and permit release of the round items 32.While suitable for many purposes, the cylindrical tube 26 shown in FIG.4 is particularly suitable for use as a seed dispenser in agriculturalapplications or in any other application wherein the time release of aplurality of objects is needed. In such an agricultural application, theseeds (i.e., analogous to round objects 32) may be released after beingsubjected to the heat of the sun during planting season.

In FIGS. 5A-5D, yet another embodiment of the process of the presentinvention is shown. In FIGS. 5A and 5AA, a planar strip or sheet 34having a plurality of openings 36 therethrough, and longitudinallyspaced through the center thereof, is shown. Strip 34 is comprised of across-linkable polymeric material and is locked into the configurationshown in FIGS. 5A and 5AA via irradiation to form a first memory shape.Thereafter, cylindrical objects 38 which may preferably consist ofnails, fasteners, terminals, rivets or other similar components areprovided through openings 36 (FIGS. 5B and 5BB). Upon heating,deformation and subsequent cooling, cylindrical objects 38 are heldtightly to strip 34 via the deformed area 40 about each of thecylindrical objects 38 (FIGS. 5C and 5CC). Finally, at any desired time,the deformed strip 34 is heated a second time (above its transitiontemperature) whereupon the strip 34, particularly deformed areas 40,will revert back to the initial memory shape (FIG. 5A) so as to releasethe several cylindrical objects 40 as shown in FIGS. 5D and 5DD. It willbe appreciated that the embodiment of the present invention as shown inFIGS. 5A-5D is particularly useful in assembly processes utilizingautomatic inserting tools for automatically dispensing heat actuatedfasteners and similar components.

In FIGS. 6A-6D, the cross-linkable polymeric material is initiallyformed in its memory shape as an open flange and comprises side wall 44having an opening 46 therebetween; and a pair or perpendicular extensionwalls 48 (which may alternatively be comprised of a cylinder). Thisconfiguration is then subjected to irradiation or other means to effectcross-linking of the polymer and attain a first memory shape. Next, adisc or other suitably shaped object 50 is fit between extended walls 48to effect closure of opening 46 (FIG. 6B). The cross-linked polymer isthen heated above its transition temperature whereupon the two endportions 52 of side extensions 48 are deformed and then cooled so as tolock and hold disc 50 in opening 46 (FIG. 6C). Thereafter, at anydesired time, the deformed cross-linked polymer may be heated above itstransition temperature so that the end portions 52 revert back to theiroriginal linear shape i.e. memory shape, and the disc 50 is thenreleased as shown in FIG. 6D. The embodiment of the present inventionshown in FIGS. 6A-6D is particularly well suited for those applicationsrequiring high temperature (i.e., heat triggered) releasing or blowouts.For example, the embodiment of FIG. 6 may be useful as a safety valve inchemical operations or as a means of releasing fire extinguishing fluidin a fire fighting system.

A similar application for the temporary holding and subsequent releasingof objects by a deformed, cross-linked polymeric material is shown inFIGS. 7A-7D. In FIG. 7A, a cross-sectional portion of a cylinder isshown generally at 54. This configuration is formed by a cross-linkablepolymeric material which is subsequently cross-linked to lock in theposition shown in FIG. 7A as a first memory shape. Next, the cylinder 54is heated above its transition temperature and deformed at its endsection 56 and finally cooled to form a retaining section 58 as shown inFIG. 7B. A disc 60 of any geometric shape is then positioned on shelf 58to thereby retain the disc or panel 60 thereon. Next, after beingsubjected to heat above the transition temperature of the deformedcross-linked polymer, end sections 56 will revert back to their originalmemory shape such that shelves 58 will be removed thereby allowing panel60 to be released and fall downwardly. A FIG. 7 embodiment of thepresent invention has many applications. For example, panel 60 mayconsist of a ceiling tile which is generally used in conjunction withwell known hung ceilings. Thus, when a fire in a building heats theceiling panel supports 54, the ceiling tile 60 will drop out therebyexposing recessed fire extinguishers (not shown) which are mountedbehind the panels. Thus, the embodiment shown in FIG. 7 may be used inmany fire and smoke prevention applications.

In FIGS. 8A-8D, an embodiment of the present invention which isparticularly useful for holding and releasing objects of complex shapeis shown. This "universal" holder comprises a planar substrate 62 havinga plurality of fingers or protrusions 64 extending therefrom. Thisparticular configuration is comprised of a suitable polymeric materialwhich, upon subjection to irradiation, will be cross-linked andtherefore locked into a first memory shape. Next, an object of complexshape, shown for example at 66 in FIG. 8B, is deposited upon theplurality of fingers 64. Fingers 64 are then heated above the transitiontemperature of the cross-linked polymer, deformed to effect a tight holdon complex object 66 and cooled down to lock fingers 64 into a seconddeformed shape as shown in FIG. 8C. As with the previous embodiments, atany appropriate time, the deformed fingers 64 which hold complex shapedobjects 66 may be reheated above the transition temperature of thepolymeric material to effect release of the objects 66 with the deformedfinger 64 reverting back to the original memory shape (see FIG. 8D).

It will be appreciated that in the embodiments shown in FIGS. 3-8, it isthe deformed cross-linked polymeric part which holds or locks in asecond object or part; and thereafter releases that second object orpart upon reheating. However, in an alternative method of practicing thepresent invention, the cross-linked deformed polymeric material may beitself held; the deformed cross-linked material releasing itself fromthe holder upon reheating. Such alternative embodiments of the presentinvention are shown in FIGS. 9 and 10. Thus, in FIG. 9A, an L-shapedshelf structure 68 having an opening 70 therethrough and defining aninner diameter D1 and a smaller outer diameter D2 is shown. Next, across-linkable polymeric material 72 having a length L which is lessthan the diameter D2 is formed and then cross-linked to lock in a firstmemory shape as shown in FIG. 9A. Thereafter, polymeric material 72 isheated and deformed to define a flat disc or plate and thereafter cooledto lock in the deformed second shape (see FIG. 9B). The deformed secondshape of cross-linked polymeric material 72 will have a new length L'which is greater than diameter D2 and equal to or less than diameter D1.Thus, as shown in FIG. 9C, flat plate 72 will rest upon the shelf 68 andthereby close the opening identified at 70. Upon a second heatingwherein the polymeric material 72 is heated above the transitiontemperature thereof, the cross-linked deformed polymer will revert backto its original memory shape having a length L (which is less thandiameter D2) and thereby fall through opening 70 as indicated by thearrow in FIG. 9D. The embodiment of the present invention as shown inFIG. 9 will function in a manner similar to the embodiment of FIG. 7.Accordingly, the FIG. 9 embodiment is well suited for use as a ceilingtile which is generally used in conjunction with well known hungceilings. This embodiment is also well suited for any other use whereinit is desired to expose or access an opening when environmentaltemperature is elevated.

Similarly, in FIGS. 10A-10D, a pipe or other conduit 74 having retainingmeans 76 (such as a flange) therein for holding or retaining a disc orthe like is shown. A cross-linkable polymeric material 78 having adiameter D which is less than the diameter defined by the inside wallsof the conduit 74 is formed and then subjected to irradiation or othermeans to effect cross-linking and define a first memory shape as shownin FIG. 10A. Disc 78 is then heated above its transition temperature,deformed and cooled to form a second deformed shape having a diameterD"; diameter D" being sufficiently large to permit retaining means 76 tohold disc 78 therein (FIG. 10B). Subsequently, as the temperature iselevated above the transition temperature of the deformed cross-linkedpolymer, disc 78 will revert back to its original memory shape (FIG.10C) and thereafter fall from retaining means 76 (FIG. 10D). Theembodiment of FIG. 10 is somewhat analogous to the previously discussedFIG. 6 embodiment and is particularly well suited for those applicationsrequiring high temperature i.e. heat triggered, releasing or blowouts.In another application, disc 78 may be used to divide several chamberssuch as chambers 80 and 82 in FIG. 10B. Thus, the embodiment of FIG. 10may be used as a seal which permits heat actuated destruction thereofand allows mixing of several components between separated chambers.

In FIGS. 11A-11D, an embodiment of the present invention is shown whichis well suited to act as a cap or lid for closing a container identifiedat 84. In FIG. 11A, a cap or lid 86 is comprised of a cross-linkablepolymeric material and is subjected to suitable cross-linking so as toprovide a first memory shape as shown therein. The first memory shape ofcap 86 may be defined as an open ended cylinder which loosely fits overthe container 84 (FIG. 11B). Cap 86 is then heated, deformed and cooledto correspond to the shape of the neck 88 of container 84 and therebyeffect a tight or snug fit thereon. At any desired time thereafter,deformed cap 86 may be subjected to a second heating whereupon the capwill revert back to its original shape and once again be looselypositioned on container 84 (see FIG. 11D). The embodiment of FIG. 11 mayfind great utility in many different types of container closureapplications. One useful application is in providing tamper proof-typeprotections which may be easily heat releaseable i.e. by hot water.

In FIG. 12, another example of the process of the present inventionbeing utilized in conjunction with the closure of a container is shown.Thus, in FIG. 12A, a cylindrical container 90 having an opening 92 atone end 94 thereof, is shown after being subjected to cross-linking andthereby locking in a first memory shape. Next, a liquid or other fluidis provided within container 90 (FIG. 12B) and the end 94 of container90 is subjected to heat, deformed and cooled to effect a liquid-tightclosure as shown in FIG. 12C. At any desired time thereafter, end 94 ofcontainer 90 may be heated a second time whereupon opening 92 willreopen and the liquid 96 therein may be accessed for dispensing.

The temporary holding and releasing process for cross-linked polymers inaccordance with the present invention and as discussed by the numerousexamples hereinabove is well suited for multiple use applications. Itwill be appreciated that the holding and releasing of parts or objectsmay be repeated over numerous cycles. For example, in one test, 50cycles were successfully completed for (1) heating, (2) deforming toclose, (3) cooling so as to lock in the deformation and (4) reheating toopen the container such as the one disclosed in FIG. 12 hereinabove. Thecross-linked polymeric container was comprised of commercially availablelow density polyethylene (LDPE); nominal 3/16 inch outer diameter tubingwith 0.025 inch wall thickness. Heating was conducted with a lab hot airheat gun set at 420° F., deformation was effected with a pair of pliersand cooling was done with cold water. The operation was manuallyperformed but surprisingly achieved average total cycle times of 0.4-0.8min/cycle depending primarily upon time of cooling and thereforeincreased times to reheat.

While preferred embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustrations and not limitation.

What is claimed is:
 1. A process for a first part to temporarily holdand release a second part comprising the steps of:forming across-linkable polymeric first part to a first memory shape;cross-linking said polymeric first part to lock in said first memoryshape; heating said first memory shaped polymeric first part to atemperature above its transition temperature; deforming said heatedmemory shaped polymeric first part to a second deformed shape so as tohold onto and surround at least a portion of a second part; cooling saiddeformed second shaped first part to temporarily hold and surround thesecond part; and heating said deformed second shaped first part aboveits transition temperature wherein said first part will revert from itsdeformed second shape to its first memory shape and wherein the held andsurrounded second part will be released from said first part wherebysaid first part and said second part will be totally separated andindependent from each other.
 2. The process of claim 1 including:formingsaid first memory shape as a base having at least one holding meansextending therefrom, said holding means having an opening therethroughwhich is adapted to receive the second part.
 3. The process of claim 2including:forming said holding means as a cylindrical shape.
 4. Theprocess of claim 1 including:forming said first memory shape as a tubehaving a longitudinal slot therethrough defining an interior and anexterior; and deforming said tube to close said slot.
 5. The process ofclaim 1 including:forming said first memory shape as a planar sheethaving at least one opening therethrough which is adapted to receive thesecond part.
 6. The process of claim 1 including:forming said firstmemory shape as an open flange comprising a base having extensionsextending therefrom and defining an opening therebetween which isadapted to receive the second part.
 7. The process of claim 6 whereinsaid extensions define a cylinder.
 8. The process of claim 6wherein:said second part is a plate or disc.
 9. The process of claim 1including:forming said first memory shape to include a retaining shelf,said retaining shelf adapted to receive the second part.
 10. The processof claim 9 wherein:said second part is a plate or disc.
 11. The processof claim 1 including:forming said first memory shape as a substratehaving a plurality of protrusions extending therefrom, said protrusionadapted to deform and hold the second part.
 12. The process of claim 1including:forming said first memory shape as a lid comprising a basehaving sidewalls extending therefrom and defining an openingtherebetween adapted to be disposed on the second part.
 13. The processof claim 12 wherein:the second part is a container.
 14. The process ofclaim 1 wherein said cross-linkable polymeric material is across-linkable material selected from the group comprising polyethylene,polyethylene co-polymers, polyvinylchloride (PVC), elastomers, blends ofPVC and elastomers, ethylenevinylacetate (EVA) or EVA/wax blends. 15.The process of claim 1 wherein:said cross-linking is effected byirradiation or chemical additives.
 16. A holding and releasing devicecomprising:an object to be held and released; means for temporarilyholding and releasing said object, said holding means comprising across-linked polymeric material formed to a first memory shape; whereinsaid holding means is adapted to be heated above its transitiontemperature a first time and deformed to a second deformed shape so asto hold onto and surround at least a portion of said object andthereafter cooled to temporarily hold said object; wherein said deformedsecond shaped holding means is adapted to be heated above its transitiontemperature a second time whereby the holding means will revert from itsdeformed second shape to its first memory shape and whereby said heldobject will be released from the holding means; and whereby said holdingmeans and said object will be totally separated and independent fromeach other.
 17. The device of claim 16 wherein said holding meanscomprises:a base having at least one protrusion extending therefrom,said protrusion having an opening therethrough which is adapted toreceive the object.
 18. The device of claim 17 wherein:said protrusionhas a cylindrical shape.
 19. The device of claim 16 wherein said holdingmeans comprises:a tube having a longitudinal slot therethrough definingan interior and an exterior; and said tube is adapted to deform whereinsaid slot is closed.
 20. The device of claim 16 wherein said holdingmeans comprises:a planar sheet having at least one opening therethroughwhich is adapted to receive the object.
 21. The device of claim 16wherein said holding means comprises:an open flange comprising a basehaving extensions extending therefrom and defining an openingtherebetween which is adapted to receive the object.
 22. The device ofclaim 21 wherein said extensions define a cylinder.
 23. The device ofclaim 21 wherein:said object is a plate or disc.
 24. The device of claim16 wherein said holding means includes:a retaining shelf, said retainingshelf adapted to receive the object.
 25. The device of claim 24wherein:said object is a plate or disc.
 26. The device of claim 16wherein said holding means comprises:a substrate having a plurality ofprotrusions extending therefrom, said protrusions adapted to deform andhold the object.
 27. The device of claim 16 wherein said holding meanscomprises:a lid comprising a base having sidewalls extending therefromand defining an opening therebetween adapted to be disposed on theobject.
 28. The device of claim 27 wherein:the object is a container.29. The device of claim 16 wherein said cross-linked polymeric materialis a cross-linked material selected from the group comprisingpolyethylene, polyethylene co-polymers, polyvinylchloride (PVC),elastomers, blends of PVC and elastomers, ethylenevinylacetate (EVA) orEVA/wax blends.
 30. A process for a first part to temporarily hold andrelease a second part comprising the steps of:forming a cross-linkablepolymeric first part to a first memory shape comprising a base having atleast one holding means extending therefrom, said holding means havingan opening therethrough which is adapted to receive a second part;cross-linking said polymeric first part to lock in said first memoryshape; heating said first memory shaped polymeric first part to atemperature above its transition temperature; deforming said heatedmemory shaped polymeric first part to a second deformed shape so as tohold on to the second part; cooling said deformed second shaped firstpart to temporarily hold the second part; and heating said deformedsecond shaped first part above its transition temperature wherein saidfirst part will revert from its deformed second shape to its firstmemory shape and wherein the held second part will be released.
 31. Theprocess of claim 30 including:forming said holding means as acylindrical shape.
 32. A holding and releasing device comprising:anobject to be held and released; means for temporarily holding andreleasing said object, said holding means comprising a cross-linkedpolymeric material formed to a first memory shape, said first memoryshape including a base having at least one protrusion extendingtherefrom, said protrusion having an opening therethrough which isadapted to receive said object; wherein said holding means is adapted tobe heated above its transition temperature a first time and deformed toa second deformed shape so as to hold onto said object and thereaftercooled to temporarily hold said object; and wherein said deformed secondshaped holding means is adapted to be heated above its transitiontemperature a second time whereby the holding means will revert from itsdeformed second shape to its first memory shape and whereby said heldobject will be released.
 33. The device of claim 32 wherein:saidprotrusion has a cylindrical shape.